The alpha-2 agonist, clonidine, and the dopamine agonist, apomorphine, stimulate the secretion of growth hormone in normal volunteers. Both clonidine and apomorphine stimulate the secretion of GH via different mechanisms. Thus, administration of both drugs on separate occasions will provide a pattern for GH secretion. Comparisons between psychiatric pts and normal volunteers will help establish which neurotransmitter system is abnormal.